happened me 3 times 2 times in level1 and 1 time in level6 i well put a screenshot from level6 ...the problem is that i am blocked with the boss like you well see in screenshot and can't do anything just to wait the time to reach 00:00 or to alt+ctrl+Del and close the game:|....i am new player played until now 5 time lvl 1 and 1 time level 6 and from this 6 total games 3 blocked me like this:
http://img14.imageshack.us/i/bugok.png/
http://img14.imageshack.us/i/bugok.png/